It is safe to do so. However leave the "Wipe free space" unmarked as it greatly increase CCleaner clean-up time.
I do have everything else marked in my own personal use of CCleaner. I am the only user of my computer after all.
i recently downloaded the latest CCleaner version 3.0...i want to know if i should just put a check mark on everything and press run cleaner. i don't know if i should delete windows log files, DNS cache, etc...help please. thanks.